I'll just offer up the other side of the coin for balance.
I'm no means an expert pitmaster, but I hold the opinion that the sweetest smoke is light blue at the darkest and sometimes is even invisible. PF contains a lot of discussions on the subject. You can also search the Internet for similar.
I've used a few of the auxiliary smoke producing devices and they all generated white smoke that is generally thought of as harsh and undesirable. However, some people accept white smoke because they prefer strong smoke flavor. I'm not judgmental on the subject because I understand that individual tastes vary and some users reduce the harsh flavor by removing the device before it burns empty.
So, my advice is always, "Give it a try. See if you like it."